Variable rate application of side-dress nitrogen on cotton in Georgia, USA

Abstract

Uniform application of fertilizers is inefficient as it does not consider field variability. During the last decade, variable rate application (VRA) has become increasingly popular. The goal of this study was to asses VRA strategies for applying side-dress nitrogen on cotton. The experiment was done in two cotton fields in southern Georgia, USA. The experimental design consisted of two variable rate application strategies and a control. Before cotton planting, the apparent electrical conductivity (ECa) was measured. Plant vigor was estimated by measuring NDVI with an optical sensor. The results showed that the high yield is correlated with high nitrogen rates and the ECa of the soil and that profitability increases by using VRA.